Mixed reality is a technology that allows virtual imagery to be mixed with a real world physical environment. As one example, a user may wear a head-mounted display (HMD) that includes a microdisplay and an optical system that both projects an image from the microdisplay to the user's eye and allows the user to see the real world.
Constructing such optical systems provides several challenges. One problem is providing a clear and undistorted view of the real world to the user while projecting the image from the microdisplay to the user's eye.